// https://www.lintcode.com/problem/nested-list-weight-sum/

/**
 * // This is the interface that allows for creating nested lists.
 * // You should not implement it, or speculate about its implementation
 * public interface NestedInteger {
 *
 *     // @return true if this NestedInteger holds a single integer,
 *     // rather than a nested list.
 *     public boolean isInteger();
 *
 *     // @return the single integer that this NestedInteger holds,
 *     // if it holds a single integer
 *     // Return null if this NestedInteger holds a nested list
 *     public Integer getInteger();
 *
 *     // @return the nested list that this NestedInteger holds,
 *     // if it holds a nested list
 *     // Return null if this NestedInteger holds a single integer
 *     public List<NestedInteger> getList();
 * }
 */
public class Solution {
    public int depthSum(List<NestedInteger> nestedList) {
        // Write your code here
        return depthSum(nestedList, 1);
    }
    
    public int depthSum(List<NestedInteger> nestedList, int level) {
        int ret = 0;
        for (int i = 0; i < nestedList.size(); ++i) {
            NestedInteger ni = nestedList.get(i);
            if (ni.isInteger()) {
                ret += (ni.getInteger() * level);
            } else {
                ret += depthSum(ni.getList(), level + 1);
            }
        }
        return ret;
    }
}